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Theory and techniques of electrostatic charging of melt-blown nonwoven webs, TAPPI JOURNAL, January 1998, Vol. 81(1)

Theory and techniques of electrostatic charging of melt-blown nonwoven webs, TAPPI JOURNAL, January 1998, Vol. 81(1)

Tools of the hedging trade, TAPPI JOURNAL, January 1998, Vol

Tools of the hedging trade, TAPPI JOURNAL, January 1998, Vol. 81(1)

Toronto spotlight shines on tappi conference polymers, laminations, and coatings, TAPPI JOURNAL, January 1998, Vol. 81(1)

Toronto spotlight shines on tappi conference polymers, laminations, and coatings, TAPPI JOURNAL, January 1998, Vol. 81(1)

Influence of voids on the engineering constants of paper part 2: void modeling, TAPPI JOURNAL, December 1994, Vol. 77(12)

89APR177

MD microstriations in paper: a two-sided shrinkage phenomenon?, TAPPI JOURNAL April 1989

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Submit to TAPPI Journal TAPPI Journal's stringent peer-review process ensures that each issue contains the highest-quality, most relevant research. All papers submitted must pass peer review before

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Recovery boiler back-end heat recovery, TAPPI Journal March 2023

ABSTRACT: Sustainability and efficient use of resources are becoming increasingly important aspects in the operation of all industries. Recently, some biomass-fired boilers have been equipped with increasingly complex condensing back-end heat recovery solutions, sometimes also using heat pumps to upgrade the low-grade heat. In kraft recovery boilers, however, scrubbers are still mainly for gas cleaning, with only simple heat recovery solutions. In this paper, we use process simulation software to study the potential to improve the power generation and energy efficiency by applying condensing back-end heat recovery on a recovery boiler. Different configurations are considered, including heat pumps. Potential streams to serve as heat sinks are considered and evaluated. Lowering the recovery boiler flue gas temperature to approximately 65°C significantly decreases the flue gas losses. The heat can be recovered as hot water, which is used to partially replace low-pressure (LP) steam, making more steam available for the condensing steam turbine portion for increased power generation. The results indicate that in a simple condensing plant, some 1%•4% additional electricity could be generated. In a Nordic mill that provides district heating, even more additional electricity generation, up to 6%, could be achieved. Provided the availability of sufficient low-temperature heat sinks to use the recovered heat, as well as sufficient condensing turbine swallowing capacity to utilize the LP steam, the use of scrubbing and possibly upgrading the heat using heat pumps appears potentially useful.

Non-process elements in the recovery cycle of six Finnish kraft pulp mills, TAPPI Journal March 2023

ABSTRACT: In this work, the aim was to study the distribution and accumulation of the non-process elements (NPEs) in the recovery cycle of Finnish pulp mills and look at whether the geographical location (North vs. South) correlates with the current Finnish NPE levels. In addition, a comparison to older similar Finnish measurements was made with an attempt to analyze the reasons behind differences in the most typical non-process elements, aluminum (Al), silicon (Si), calcium (Ca), phosphorus (P), magnesium (Mg), manganese (Mn), chlorine (Cl), and potassium (K), taking into account the main elements in the white liquor, sodium (Na) and sulfur (S). The extensive laboratory results gained in this study are from seven sampling points at six pulp mills and present analytical data of metal concentrations. The data obtained presents an update to previous NPE studies. The levels found did not statistically differ between North and South Finland. The NPE levels, apart from phosphorus, found in Finnish pulp mills today have not changed considerably compared to the levels in earlier investigations in the 1990s. In the newest data, the phosphorus concentration was consistently higher in the as fired black liquor, electrostatic precipitator (ESP) ash, lime mud, and green liquor than in the previous results. In addition, the levels of Al, Si, Ca, P, and Mg in recovery boiler ESP ash were consistently higher compared to the older results. As the mills start to close their systems more, a stronger accumulation of NPEs can be expected, increasing the likelihood of more operational problems in the process. Further understanding of where the NPEs accumulate and how they can be most effectively removed will be valuable knowledge in the future.